Recently, in the field of endoscope, a swallowable capsule endoscope equipped with an imaging function and a radio communication function has appeared. The capsule endoscope is configured to take images during an observation period after the capsule endoscope is swallowed by an examinee as a subject for observation (examination) until naturally discharged from a body of the examinee, sequentially while passing through internal organs (inside body cavities) such as a stomach and a small intestine according to the peristalsis thereof.
Moreover, image data obtained inside the body cavities by the capsule endoscope during this observation period while moving inside these organs is sequentially transmitted to an external device provided outside the subject by radio communication based on a predetermined sequence, and stored in a memory. If the examinee carries the external device having this radio communication function and the memory function, the examinee can freely move without having any inconveniences during the period from swallow of the capsule endoscope until discharge thereof. After the image data is acquired, doctors or nurses can perform diagnosis based on the image data stored in the memory of the external device by displaying an image of the body cavities on a display unit such as a display.
To control activation of the capsule endoscope, such a configuration has been proposed that a lead switch to turn on and off by an external magnetic field is provided in the capsule endoscope, and a permanent magnet to supply a magnetic field is provided to a package of the capsule endoscope. Specifically, the lead switch provided in the capsule endoscope has a configuration so that the lead switch maintains an off state under an environment in which the external magnetic field having intensity higher than predetermined intensity is applied, and switches to turn on when the intensity of the external magnetic field is lowered. Therefore, in a state of being packed in the package before being swallowed, power supply from a power source such as a battery to electric components of a device or the like having the imaging function and the radio communication function is cut by this magnet, and the capsule endoscope is not activated, thereby preventing waste of the battery. On the other hand, at the time of being swallowed, the capsule endoscope is unpacked from the package to be separated from the permanent magnet and released from the influence of the magnetic force, and the power supply cut to the electric components is canceled. Thus, power is supplied to the above electric components of the capsule endoscope, and acquisition and transmission of images are performed. With this configuration, it is possible to prevent actuation of the capsule endoscope while the capsule endoscope is packed in the package (For example, see FIG. 1).    Patent Document 1: International Publication No. WO/0135813 Pamphlet